Method of making heat transfer pipe



v.1. w. BROWN, JR

METHOD OF MAKING HEAT TRANSFER PIPE May 14, 1940.

Filed June 7, 1958 wm v fia 2 INVENTOR.

BY v M ATTORNEYS Patented May 14, 1940 UNITED STATES PATENT OFFICE JohnW. Brown, Jr., Lakewood, Ohio Application June 7, 1938, Serial No.212,285

4 Claims.

This invention relates to improvements in heat transfer pipes and methodof making same. The invention has to do with a heat radiating orabsorbing unit consisting of a pipe upon which are cast fin sectionsthat completely enclose the pipe and are connected to each other byfluidtight joints formed in the casting operation. In this manner thepipe is protected against the action of moisture, gases or the like.Preferably the fin sections are formed of a non-ferrous metal, notsubject to rapid oxidation, such for example as aluminum, while the pipeitself is usually. iron or steel and when left partially unprotected, ashas been the case heretofore, is subject to rapid deterioration becausevof rust.

One of the objects of the invention therefore is the production ofprotected pipe units having heat radiating or absorbing fins, and theexclusion of moisture from the joints between, adjacent sections of theunit.

Other objects and features of novelty will appear as I proceed with thedescription of those embodiments of the invention which, for thepurposes of the present application, I have illustrated in theaccompanying drawing, in which Fig. 1 is a central longitudinal sectionof a fragment of a pipe unit embodying the invention.

Fig. 2 is a cross section taken substantially on a line 2-2 of Fig. 1.

Figs. 3 and 4 are sectional detail views, similar to Fig. 1, showingmodifications of the invention.

In carrying out the invention, as for instance.

in making an expansion unit for a refrigerating plant, a length of pipel of suitable dimensions forms the trunk of the article. Seamless steeltubing is a suitable material for this purpose. This pipe is to beprovided with spaced heat transferring fins formed preferably, althoughnot necessarily, of a metal having high heat conductivity, aluminum forexample.

The fins, shown at H in the drawing, appear as a series of disksintersecting the pipe at right angles. They are in fact annular flangeshowever, which taper outwardly in cross section, and are cast integralwith cylindrical hubs that surround and grip the pipe tightly. Each finsection also has a neck on the side of the flange opposite the hub. Inthe drawing the hub is marked l2, l2 and 12" in Figs. 1, 3 and 4,respectively, and the neck in the same figures is marked l3, l3 and I3.These parts are somewhat diiferently formed in the difierentmodifications, but essentially they are the same, the neck beingrelatively short and of smaller'external diameter than the hub, thelatter extending along the pipe to the next fin section and overlappingthe neck of that section.

The fin sections, each consisting of a hub, a neck and at least oneflange, are cast one at a time in place on the pipe, preferably by thedie 5 casting method. In other words, one section is cast on the pipe,the die opened and the pipe with its cast section moved along, when thedie is again closed and the next fin section cast. a short time intervalbeing allowed to intervene in order to permit the finished casting tocool somewhat and contract tightly against the pipe and against the neckof the preceding section.

An important feature of the invention is the provision of the necktogether with the casting of the hub of the succeeding section aroundthis neck, so that when the hub cools it will contract around the neckof the preceding section and form a joint that is fluid-tight.

It is to be understood, of course, that each section as cast, instead ofincluding a single flange, may comprise two or more flanges.

By following the procedure above outlined the ferrous metal pipe I0 iscompletely enclosed in a non-ferrous metal jacket, and the succeedingsections of this jacket are so connected together that it is impossiblefor moisture to enter between them and cause deterioration of the pipe.The method also accomplishes the manufacture of heat transfer pipes ofhigh efficiency at a rela tively low cost and without machine work ofany kind.

Having thus described my invention, I claim:

1. The method of forming heat transfer fins on pipe, which comprisescasting one fin section 5 at a time on the pipe with a neck at one endof the section surrounding the pipe and a hub portion at the other endof the section surrounding the pipe and overlapping the neck of thepreviously formed section.

2. The method of forming heat transfer fins on pipe, which comprisescasting one fin section at a time on the pipe with neck and hub portionson the opposite ends of the section surrounding the pipe, permitting thecasting to cool sufficiently to tightly grip the pipe, and then castingthe next fin section on the pipe with a neck and a hub portion, saidlast named hub portion overlapping the neck of the previously formedsection, and permitting the last named section to cool and contract,whereby a tight joint is formed between the two sections and moisture isexcluded.

3. The method of forming heat transfer fins on pipe and protecting thepipe from the weather, which comprises casting one fin section at a time55 10 and heat transferring nns on a length oi pipe,

which comprises casting on the pipe a section oi metal having an annularflange with a pipe enclosing hub on one side 01 the flange and a, shortneck on the other side thereof. and thereafter casting asimiiar metalsection adjacent tothe first named section with the hub portion of thesecond section surrounding and gripping the neck oi the first section,whereby a fluid-tight joint is formed between the sections.

JOHN W. BROWN, Jl.

